Is Polyamory Legal? The US, Canada, the UK and Europe
In general, yes: polyamory is legal. Having more than one loving or sexual relationship with consenting adults is not a crime anywhere in the US, Canada, the UK or the EU. What is illegal is bigamy, meaning marrying more than one person at the same time. So you can love, date and live with more than one partner, but in North America and Europe you can only be legally married to one of them.
That is the headline. The rest of this article covers the details people most often ask about. Please read it as general information, not legal advice. Laws change and vary by state, province and country, so if something matters to your situation, talk to a lawyer where you live.
Relationships vs marriage: the key distinction
The law mostly cares about two things: marriage, and what adults do in private with consent.
- Relationships between consenting adults are generally a private matter. Dating several people, being honest with all of them, even living together as three or four, is not illegal.
- Marriage is a legal status the state controls. Every country covered here allows marriage between two people only. Trying to marry a second spouse while the first marriage still stands is bigamy, and bigamy is illegal across the US, Canada, the UK and the EU.
Most polyamorous people never come near bigamy laws, because they are married to one partner or to nobody. Some hold commitment ceremonies with other partners. These have no legal effect, and generally that is the point: they are about meaning, not paperwork.
The United States
Across the US, polyamorous relationships between consenting adults are legal, and bigamy is illegal in every state. A few developments are worth knowing:
- Utah, 2020. Utah reduced bigamy among consenting adults from a felony to an infraction, roughly the level of a traffic ticket. It is still not allowed, but the penalty changed dramatically.
- Somerville and Cambridge, Massachusetts, 2020 and 2021. These two cities recognised domestic partnerships with more than two people. These are local partnership registrations, not marriages, and they mainly matter for things the city itself controls.
- New York, 2024. New York repealed its old law that made adultery a crime. That law had been rarely enforced for decades, but its removal was widely seen as a sign of changing attitudes.
A handful of US states still have old adultery laws on their books, though they are rarely if ever enforced. In some states, adultery can still play a role in divorce proceedings. If you are married and your spouse has not agreed to the arrangement, that is a very different situation, both legally and ethically. Our article on whether an open relationship is cheating covers the ethical side.
Canada
In Canada, consensual relationships between adults are legal, and bigamy and polygamy, meaning multiple marriages, are criminal offences. Living openly with more than one partner without trying to marry them is generally a private matter.
Canada is also known in lifestyle circles for R. v. Labaye, a 2005 Supreme Court case. The court held that a swingers club where consenting adults met was not indecent. It is about swinging rather than polyamory, but it reflects a general legal attitude that private consensual activity between adults is not the state's concern. Our guide on whether swinging is legal goes into that side.
The United Kingdom
In the UK, relationships between consenting adults are legal, and bigamy is a criminal offence. There is no legal recognition of relationships with more than two people. Cohabiting partners, even in a couple, have fewer automatic rights than many people assume, so polyamorous households in particular benefit from written agreements and wills.
The European Union
No EU country recognises marriage to more than one person, and bigamy is illegal across the EU. Consensual adult relationships are legal. Some countries offer registered partnerships or civil unions, but these are for two people. As in the UK, the main practical issue is that the law is built around couples, so multi-partner households have to protect themselves with private documents.
Where polyamorous people actually run into trouble
Criminal law is rarely the problem. The practical issues are more ordinary:
- Inheritance. Without a will, an unmarried partner may inherit nothing. Write a will, and update it when relationships change.
- Medical decisions. If you are in hospital, who can speak for you? A healthcare proxy or power of attorney lets you name the people you trust.
- Property and money. If three people buy a home together, a written agreement about who owns what and what happens if someone leaves can save a lot of pain.
- Children. Parenting law in most places assumes two parents. If a third adult helps raise a child, their role may have no legal standing without specific arrangements. Get local advice.
- Custody disputes. In a contested divorce or separation, a parent's relationship style can come up. Courts generally focus on the child's welfare, but how that plays out varies a great deal.
- Work and housing. In most places, the law does not specifically protect people because of their relationship structure. Many people choose discretion at work for this reason. Our guide to discretion and privacy has practical tips.
An illustrative household
Claire, Martin and Joanna share a house in Toronto. Claire and Martin are married. Joanna has been with both of them for five years. Nothing about their life is illegal. But when Joanna had surgery last year, the hospital initially only wanted to speak with "family". After that, all three made healthcare proxies, updated their wills and wrote a simple agreement about the house. None of it was expensive, and all of them sleep better.
That pattern is common. The law rarely forbids polyamorous life. It just does not plan for it, so you have to.
Talking about it with others
Legal or not, polyamory can raise eyebrows. If you are asked, a calm answer usually does the job: "Everyone involved is an adult, everyone knows, everyone agreed. Nobody's married twice." For more, see our guide to explaining non-monogamy to friends and family, and if you are new to the whole idea, start with what polyamory is. Couples considering an open marriage will find the same legal basics apply.
The bottom line
Polyamory between consenting adults is legal across North America and Europe. Marrying more than one person is not. The real work is practical: wills, proxies and agreements that make sure the people you love are protected.
If you would like to meet open-minded couples and single women who have sorted out these questions in their own lives, you are welcome to join Rope & Candy. It is free, and the conversations tend to be far more fun than the paperwork.
Questions people ask
Is polyamory legal in the United States?
Being in more than one relationship between consenting adults is legal across the US. What is illegal is bigamy, meaning marrying a second person while already married. This is general information, not legal advice.
Can you marry more than one person anywhere in North America or Europe?
No. Bigamy is illegal across the US, Canada, the UK and the EU, and none of them recognise marriage to more than one person. A few US cities, such as Somerville and Cambridge in Massachusetts, recognise multi-partner domestic partnerships, which are not marriages.
Can my polyamorous relationship affect a divorce?
It can, depending on where you live and how the divorce is handled, especially around custody or fault. Laws differ a great deal between states, provinces and countries, so speak to a local family lawyer if this applies to you.
How can polyamorous partners protect each other legally?
Common steps include wills, powers of attorney, healthcare proxies and written cohabitation or property agreements. A local lawyer can tell you which documents carry weight where you live.